(1) Field of the Invention
The present invention relates to an image recording and replaying apparatus and method, and specifically to an image recording and replaying apparatus and method that allow image data recorded by a repeat recording to be replayed during the repeat recording, where the “repeat recording” refers to the recording of recently received image data so that the recorded image data does not exceed a predetermined amount that ensures a predetermined time period of replay, by continuously deleting earlier-recorded data.
(2) Description of the Related Art
In recent years, a unique TV receiver came on the market which has an accumulation-type set-top box (STB) containing a large-capacity hard disk drive. With such a construction, the TV receiver provides a repeat recording feature in which the TV receiver continues to record broadcast image data so that the recorded image data does not exceed a predetermined amount that ensures a predetermined time period of replay while the viewer watches the broadcast program, and on request allows the viewer to watch a scene he/she missed by replaying the scene which has been recorded in the repeat recording (hereinafter, such a replay is referred to as “delay replay”).
FIG. 1 shows a conventional repeat recording performed by a conventional image recording and replaying apparatus. The image data is recorded and deleted onto/from a recording medium in units of files (blocks) each of which has a capacity equivalent to a replay time period of, for example, 5 minutes. It is supposed in this example that the viewer has specified “90 minutes” as the repeat recording time period, which is in reality converted to an amount of image data to be recorded to ensure the specified time period of repeat recording. In such conditions, the storage may have (a) a file for recording most recently received image data and (b) 90 (minutes)/5 (minutes)=18 files that record image data that have been received immediately before the most recently received image data. The files having recorded image data earlier are deleted in sequence after 90 minutes elapse since the image data has been recorded into the files.
As shown in FIG. 1, a current recording point is in the file “block 20”, and the file “block 1” recording older data has been deleted.
If the user requests the delay replay with specification of the normal replay in this condition and the delay replay starts with the image data in the file “block 2”, the delay replay is performed appropriately since the replay point moves as the recording point moves (that is to say, when the replay point moves to the file “block 3”, the recording point moves to the file “block 21” which is not illustrated, and then the file “block 2” is deleted).
It should be noted here that in the above conventional example, image data is recorded and deleted in units of files (blocks), but instead of this, image data may be recorded in one file and older portion of the recorded image data may be overwritten with recently received image data, with this procedure being repeated as necessary.
However, the above-described conventional technique has the following problems.
First, the conventional technique does not support the delay replay by a special replay such as “rewind”, “pause”, or “slow replay”. For example, if the user requests the delay replay by a slow replay in the same condition as shown in FIG. 1 and the slow replay starts with the file “block 2”, then it may happen for example that when the recording point moves to the file “block 21”, the file “block 2” is deleted while the replay point stays at the file “block 2” without moving to the file “block 3”. This gives the user an inconvenience that the replay of the file “block 2” abruptly stops and skips to the file “block 3”. It is expected that similar problems may occur to the other special replays in terms of the delay replay.
If, to solve the above-described problem due to the slow replay, the deletion of the file “block 2” was canceled, image data would be recorded in the recording medium without limitation, well extending the predetermined amount corresponding to the specified time period for the repeat recording.
In the case where older image data is repetitively overwritten with newer image data, it may happen during the delay replay that the recording point reaches the replay point, causing the repeat recording to stop, without input of a stop instruction by the viewer.
In the case of fast forward, the replay point may reach the recording point. When this happens, the recording of image data onto the recording medium is intermingled with the reading of image data from the recording medium.